Hey alpha123 I am glad to hear that you have not had an EA or PA. I am a guy and have had some problems with using porn to selfsooth instead of puting myself "out there" and to be sexually rejected. Now it doesn't seem that this would be a case in your relationship. I am glad that you have a permisive view of it and your guy using it the idea that all men who watch porn are "perverts" can push the issue into a place where it becomes not only about self-soothing or self-pleasure but into a realm of secrecy and shame that does far more damage to any relationship.
You seem to have an idea of what may be the issues and he could be turning to porn as a way to protect himself from the possibility of you leaving, again. You could ask him but there is the problem that he may not even know himself why is turning to porn and not to you.
You make it sound like this has been going on for 10 years and that he has always avoided intimacy but you were ok with it as long as you were "getting" sex, please correct me if I am reading into this more that is there.